Hello
check the telegram video in the bolt IOT course.
create a telegram public channel
create a telegram BOT via BotFather
set the bot as administration in your channel.
after that you can send message to your channel by using an HTTP GET request to the telegram BOT API at the given url https://api.telegram.org/bot[BOT_API_KEY]/sendmessage?
chat_id =[MY_CHANNEL_NAME]&text=[MY_MESSAGE_TEXT]

You have to append your token directly to “https://api.telegram.org/bot” I can see an opening bracket “(” in the error message url.
If your bot token is “Je3nf5Il6rHfDN340” then the URL will be:
https://api.telegram.org/bot
Je3nf5Il6rHfDN340/sendmessage?chat_id= MY_CHANNEL_NAME&text= myMessage